My I phone is new and I would like to get Apple TV free for one year

The duration of the offered free period depends on the day of activation (first use), as that has changed per July 1st. Newer devices get a 3 months offer now.

Also don’t wait too long with redeeming, as the offer is valid during the first three months.

To redeem the offer, open the TV app on your new eligible device, and find the “Enjoy <x time> Free” redeem button there.

Read here how to redeem in more detail: Apple TV+ offer - Apple

Read here about the conditions: Apple TV+ offer - Terms and conditions - Apple

Read here if you have trouble redeeming: If you can't redeem your promotional trial of Apple TV+ - Apple Support